The present invention relates to muramyldipeptide derivatives which have adjuvant activity and are useful as a component of influenza virus particle-like artificial membrane vaccine, so-called virosome vaccine. The present invention also relates to an influenza vaccine comprising a complex of the muramyldipeptide derivatives and an influenza virus antigen.
Since the effectiveness of presently used influenza HA vaccines varies due to mutations which occur on hemagglutinin molecule of the prevailing virus, it is eagerly desired to develop more effective vaccines than the conventional ones.
As for the recent approaches in influenza vaccine development, a component vaccine consisted of HA (hemagglutinin) and NA (neuraminidase) as main ingredients or influenza virus particle-like artificial membrane vaccine made from 6-0-(2-tetradecylhexadecanoyl)-N-acetylmuramoyl-L-alanyl-D-isoglutamine, so-called virosome vaccine, are known [see Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. 61-282321]. It is known that particularly the latter exhibits an excellent effect of improving antibody value in the blood and the utilization thereof is expected.
However, this vaccine irritates a part of a human body to which it is applied to cause a redness as an undesirable adverse reaction and it is not satisfactory as a medicine.